The traditional industrial agitator usually conducts no regulation or regulates the speed in mechanical method. The speed regulation in mechanical method will increase the loss of the industrial agitator. Meanwhile, the industrial agitator will work in fluctuating status. Furthermore, it will also work in the status of "big rated power with small load power", which is quite not economic. The motor power of the industrial agitator in operating under the frequency conversion speed control is similar to its characteristics of the revolving speed and pump load. Using VFD for speed regulation will obtain a substantial power saving rate.